Help me fina a book I read as a kid, short animal stories, one about visiting a grouper on a coral reef.

I remember having this book read to me at my grandmother's, probably 35 years ago when i was 7 or so, and it might have already been old at that point. I think it was a collection of animal stories. The one I remember was about a Diver exploring a coral reef and making friends with a grouper. Gor some reason I also remember that he talked about a checkerboard colored fish. I remember it being a pretty thick book. Sorry, that's all I remember.